Various document processing systems, such as in an inserting machine, require that a document is aligned relative to a particular station in the system prior to being processed at the station. Typically, this is accomplished by registering a particular edge of the document in a particular direction in the system. For example, documents must be aligned before being conveyed to a folding apparatus to achieve a proper fold. Also, enclosures which are to be inserted into an envelope should be aligned relative to the envelope prior to insertion in order to avoid processing difficulties. Furthermore, some documents which are to be transported away from a particular queuing station, to another adjacent document raceway, should be aligned at the queuing station relative to the raceway, in order to facilitate the processing of the documents.
Devices which register a particular edge of a document to a particular direction are known. See, for example, U.S. Pat. Nos. 3,637,203, 4,078,790 and 4,925,180, which utilize stops that pivot into position to stop the advancement of documents being conveyed in a particular direction. Some registration devices, such as stationary side guides, perform the task of aligning the document while the document is being conveyed. Other registration devices, such as a "queuing" station, perform the dual task of aligning the document and stopping the document until the next successive station is ready to receive the document for further processing. Typically, queuing stations comprise mechanisms which register the document by stopping or queuing the document and which are subject to frequent mechanical failure because of the complex nature of their mechanical design. Document registration devices should be able to repeatedly process a great number of documents before repair or replacement is necessary.
In U.S. patent application Ser. No. 808,863, filed on Dec. 17, 1991, and assigned to the assignee of the present invention, a document registration apparatus in the form of a queuing station is disclosed. The apparatus has a plurality of registration stops for stopping motion of a document and registering a particular edge of a document to a particular direction in the apparatus. The registration apparatus also includes at least one urge roller for moving the registered document away from the apparatus for further processing. The document registration apparatus also includes a jam access hinge for providing access to a jammed document. However, the apparatus disclosed in U.S. patent application Ser. No. 808,863 does not include means for adjusting for skew to properly set the alignment.
A drawback present in some known document registration devices is that it can be difficult to adjust the device to the proper alignment. It is well known that there is a need to adjust such registration devices for skew. Adjusting for skew aligns the registration device so that the document is conveyed from the registration device parallel with the center line of the paper path. For a stationary device, such as with side guides, this would not be a difficult task. However, for other devices, such as a queuing station which comprises a plurality of components and performs multiple tasks, each of the individual parts must be aligned relative to each other in order for the overall apparatus to be properly aligned to a particular chosen direction without interfering with the stopping mechanism. Furthermore, once the alignment is set at a station, further adjustments may become necessary to maintain alignment. In particular, adjustments may be needed when the type of documents being processed is changed, or when the registration device goes out of alignment causing skewing of the documents at the next successive station. When the number of parts in the registration device is large, the alignment adjustment can be time consuming.
A document registration apparatus which simultaneously queues and aligns a stack of documents can also suffer from drawbacks associated with the mechanical design of the apparatus. For example, the design and operation of a queuing station may result in undesirable "shingling" of documents where the top document in the stack is not directly above the lower documents but slightly shifted forward or backward. This can occur, for example, when the exit pinch rollers are mounted in such a way that the transport system cannot maintain a square alignment when a document stack exits the station.